Multi-display tube



Aug. 19, 1958 .E. W..$MITH 2,848,638

MULTI-DISPLA! TUBE Filed June 9, l953 2 Sheets-Sheet 1 INVENTOR.

EDWIN W. SMITH Aug. 19, 1958 Filed June 9, l953 E. W. SMITHMUL'I'I-DISPLAY TUBE 'llllllllllll llll/lllllllllll ll/llllllllllllll.

2 Sheets-Sheet 2 ZNVENTOR.

2,348,638 Patented Aug. 19, 1958 and MULTI-DISPLAY TUBE Edwin W. Smith,San Diego, Calif.

Application dune 9, 1953, Serial No. 350,621

6 Claims. (Cl. 313-4695) (Granted under Title 35, U. S. Code (1952),see. 256) The invention described herein may be manufactured and used byor for the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

This invention relates in general to display devices, and morespecifically to a glow discharge tube for selectively displayingnumerals, letters, or other characters, symbols or patterns.

It is an object of the present invention to provide a sensitive displaydevice which is capable of selectively displaying any one of a pluralityof characters or symbols in substantially the same display space.

A further object is to provide a display device wherein a plurality ofcomponent parts of characters may be selectively displayedsimultaneously to form various characters consisting of combinations ofsuch component parts.

Another object is to provide a multi-di play device which basically issimple and rugged in construction and is adaptable to mass productionprocesses.

Still a further object is the provision of a multi-display device whichlends itself to a compact package construction such that space requiredon electronic equipment for its use is only slightly more than the areaof the display itself.

Another object is to provide a display device which may readily be usedside by side in an array or, if desired, may incorporate a number ofdisplay assemblies in a single envelope.

It is another object to provide a multi-display device which can provideboth line and area displays.

Still another object is to provide a display device which may beutilized in pictorial or cartoon type presentations utilizing both lineand area presentations.

A still further object of the invention is to provide a display devicewhich will visually display range and bearing data on a coordinatesystem.

It is a further object to provide a display device which visually willindicate point on a rectangular, polar, or other coordinate system.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

Fig. 1 is a perspective view in partial fragmentary section of aphysical embodiment constructed in accordance with my invention;

Fig. 2 is an exploded view of the display assembly shown in Fig. 1;

Fig. 3 is a perspective view in tregmentary section of a modification ofa pattern component of the display assembly;

Fig. 4 is a perspective view in fragmentary section of a secondmodification of a pattern component of the display assembly;

Fig. 5 is a schematic fragmentary sectional view of a display assemblyillustrating one mode of operation;

Fig. 6 is a schematic view similar to Fig. 5 illustrating a second modeof operation;

Fig. 7 is a further modified form of the invention; and

Fig. 8 is still another modified form of the invention.

In the well-known space discharge devices or glow lamps a pair ofmetallic electrodes are sealed within a glass bulb filled with neon,argon, or other suitable gas at a suitable low pressure. When aunidirectional (direct current) potential of sufiicient amplitude isapplied to the electrodes a glow discharge will be initiated in thespace between the two electrodes. The luminous glow discharge isproduced by negative electrons and positive gas ions and takes place inthe space between the two electrodes within a certain small distancefrom the exposed surface of the cathode or negative electrode.

A number of previous glow lamp display devices have made use of thisluminous discharge adjacent to the cathode by providing a multiplicityof cathodes shaped in the form of the desired characters. The luminousdischarge adjacent to the actuated cathode then produces a luminousoutline of the character desired. In such previous devices alternativedisplays are made possible by mounting formed cathodes (such as smallwires shaped in the characters desired) one behind the other or bydisplacing the separate cathodes laterally across the face of the tube.In the first type of construction there are several disadvantages: (1)front cathodes tend to obscure those at the rear; (2) construction isdiflicult; and (3) there may be difliculty in getting the glow dischargeto cover the wire uniformly. In the second type of construction whereinsuccessive images are displayed laterally, one of the principalobjectives of the present invention is not achieved; i. e., alternativedisplay of characters in essentially the same display space.

The present invention utilizes a basic principle for multidisplaydifferent from that utilized by the tubes just described. Rather thanemploying several discrete cathodes shaped in the form of the desiredcharacters the present invention employs a display area composed of manyglow discharge holes or cells. These cells are selectively fired inappropriate groups, to display the characters or patterns desired.

in wire or similar type display tubes, as has been mentioned supra,ditficulty may be experienced in getting all of the exposed electrodearea to glow. Increasing voltage may merely cause an increase inintensity of the parts already glowing, without causing the remainder ofthe surface to glow. In the present invention, each cell is partially ifnot entirely independent of ionization or lack of ionization of itsneighbor. This is an important advantage, since an increase of voltagewill cause the selected cells to ionize and thus glow.

One embodiment of the invention is shown in Figs. 1 and 2, wherein atube 10 is provided having a glass envelope 11 which is filled with asuitable gas, such as neon, at the required pressure for such gas. Theglass stem 12 of the tube 10 has fused into it a plurality of supports13 which hold a display assembly 14 adjacent the glass viewing surface15 of the envelope 1]..

The display assembly 14 is comprised of a sandwich of alternatelyinsulating laminations 2t and conductive electrodes 21 and 22. Theassembly 14 may be held together as with riveted pins 28, clips, and/ orsuitable cement having good insulating qualities, or by other suitablemeans. These insulating laminations 2i and electrodes 21 have formedtherein a plurality of holes 23 which, when the insulating laminationsand electrodes are assembled, are in alignment. These aligned holes 23are loosely sealed at the front of the assembly 14 by a transparentcover plate 24 and at the back by a rear cover plate 22, and thus form aplurality of cells 26 corresponding number to the number of holes23'inone tern components 31. a construction is quite adaptable to massproduction tech- .thosein the insulatinglaminations 20. Duringfillingand sealing ofiof. the tube 18, the gas with which thetubeis'filled penetrates into and fills the cells 26.

i The thin conductive pattern electrodes embedded "between theinsulating lamiuations Zllare each connected to a pattern lead-out wire25. The lead-out wires are connected each to a. separate externalelectrical connecting post, such as a base prong .27. in orderto preventfiring between the lead-out Wires 25, it is desirable 'in most casestohave the exposed portions of these conductors insulated, as with asuitable ceramic insulating material. In some modes of operation (asdescribed infra), such as Where either the front plate 21a or rear plate22 is to be used as the cathode, it may only be necessary to insulatethe lead-out Wire connected to this electrode. 7

Whensulficient voltage is applied (i. e. equal to the iom'zationpotential or firing point) between any character electrode 21]; andeither the front or back electrode plates, 21a or 22, a glow dischargeisset up in all cells 26 connected with the energized pattern electrode211;. Cells not connected to that era similarly energized patternelectrode are not fired. if another pattern electrodeZlb is energizedwith an ionization potential, the glow cells 26 associated with thispattern electrode are *tired producing an alternative pattern. In otherwords, a

pattern of glow cells 26 is selectively fired, depending upon whichpattern electrode'or electrodes 21b are energized. If desired, two ormore pattern electrodes 21]) might be energized at the same time, incombination with either the front or back electrode plate, thusproducing a composite display of the two or more patterns.

The viewing surface 15 of the tube may be either transparent ortranslucent. It may be made translucent as by using ground glass for theviewing surface or by securing mica thereon. By using a translucentviewing surface 15, as shown in Fig. l, glow patterns produced in thecells 26 will appear as projected images on this viewing surface 15,thus providing extremely wide-angle viewing. The various displays thusprovided are not only in the same area but on the same surface. It willbe apparent that in lieu of using a translucent surface 15, the frontcover plate 24 might be made translucent if desired.

In Fig. 3 there is shown an alternative construction for the assemblycomponents. In this modification the dis-' 'play assembly (not shown)may be made up of a plurality of unitary pattern components generallydesignated 31, together with front and rear electrode and/or coverplates as inthe first described embodiment. The thickness of thecomponent 31 is exaggerated in order to clearly-show the detailsthereof. Each of the pattern components has a perforated insulatingsheet 32 with a thin layer 33 of conductive material connecting adesired pattern of holes 34. A lead-out wire may readily be secured tothe conductive coating or layer 33. The holes 34 in each of theperforated sheets 32 are formed for alignment upon assembly of thevarious desired pat- It will readily be seen that such a niques andprovides for ease of assembly. This embodiment, as well as the nextfollowing embodiment, lends itself to printed circuit techniques.

As a further alternative to the use of separate insulating laminations20 and pattern electrodes 21, Fig. 4

shows "a modification inwhich each pattern component 41'has a perforatedconductive sheet 42 which is covpatterns.

The coating covers the entire sheet 42 including all holes '43 exceptthose holes 4341 forming the desired pattern .mass production techniquesand'enables one to assemble readily and easily a complete sandwichassembly by selecting the desired pattern components 41.

It will thus be apparent that practical construction of the displayassemblymay be accomplished by any of several different approaches whichmight include depositing conductive layers on thin perforated insulatingsheets, such as mica or glass; utilization of conductive perforatedsheets, thedesired inactive portions of which may coated with suitableinsulating enamel or porcelain, leaving the edges of only the desiredactive holes exposed; or assembly of perforated metallic laminations cutto connectwith the desired holes, insulating one from the other asbyperforated mica, glass, or other-suitable insulatingmaterial. V v

Among the various modes of operation possible with the type ofconstruction described are: l g V 7 V a. Mode 1.The internal patternelectrodes 2111. may be operated as cathodes and either the frontelectrode plate 21a or the rear electrode plate 22 asan anode, in whichcase the glow will be produced internally in the cells in an area closeto the internal electrodeslactuated, as shown schematically for examplein Fig: 5. In Fig. 5 there is shown schematically in fragmentary crosssection a pair of cells, one 26b energized, and the other 260 notenergized. The pattern electrodes as shown in this figure as well asFig. 6 are inlaid on thesurface of the various insulating laminations29. The glowis indicated at 53, near the energized pattern electrode2112. With this mode of operation front cover plate 24 or other similararrangement to prevent cross-firing is not necessarily required. Y

b. Mode 2.-The internal pattern electrodes 21b may be operated as anodesand the front electrode plate 21a operated as the cathode in whichinstance the glow'patterns will be produced close to the front electrode21a, near the front surface, as shown schematically at 63 in Fig. 6,regardless of which pattern electrode 21b is actuated. For most displaysthis mode of operation would provide the more desirable display forwide-angle viewing. However, a tighter type of construction of the cellsis required, in order to prevent cross firing of'cells on the frontsurface. With this mode of operation the cathode, where most of thedeterioration takes place, may if desired be made a relatively heavyelectrodepas shown in Fig. 2, while each inner pattern electrode 21bwith its adjacent insulation need have a thickness of only a few mils,so that all the letters of the alphabet can be provided by an assemblyof practical proportions. For example, in one tube which has beenconstructed, a display assembly having pattern electrodes for ten digitshas a sandwich thickness of less than /s inch.

0. Mode 3.Alternating voltage may be applied between the front and backplates 21a and 22. The pattern electrodes 21b may then be employed ascontrol grids to control the onset of ionization in the pattern holesbetween the front and back electrodes by varying the ionizationpotential which is required across the front and back electrodes to firethe various pattern holes. Many variations in operation are possible inorder to obtain various desired effects. By energizing the externalleads applicable to two or'more groups of cells simultaneously, thecomposite pattern appropriate to the actuated groups can be produced.Thus a growingf or a diminishing composite pattern can be produced. -Or,for advertising or novelty purposes, the effect of m'otion can beproduced through the energization of successive Or if multipleanode/cathodes as well asmultiple cathode/anodes are provided inpatterns, thedisplay can be made a function of two variables, one setapplied to the anodes and one set to the cathodes.

Depending upon the voltage and current characteristics, gas pressure,materials employed, and details of construction, there is always more orless atomization of the cathode in a glow tube due to ion bombardment ofthe cathode. Particles of metal bombarded ofi may settle on the viewingwindow, tending to obscure the glow pattern. Operation of the tube atminimum current will minimize this effect. Treatment of the cathode byone of many processes common to the neon tube and gas tube art will alsohelp to prevent this possible difiiculty. If Mode 2 operation isemployed, undercutting of the cathode between two insulating wafers willtend to confine the particles to the immediate vicinity of the cathode.

Fig. 7 illustrates a further modification of the invention in which theanode and cathode group connections are arranged in spaced apart lines71 and 72 at right angles to each other and on opposite sides of aperforated insulating sheet 73. Either one or both of the groups ofelectrodes 71, 72 may be perforated. In this embodiment the position ofthe illuminated spot (i. e., energized cell) will correspond to thex-coordinate and y-coordinate circuit actuated. Obviously, in lieu ofusing a single sheet 73, a plurality of perforated sheets could be usedwith one or more electrodes 71 or 72 arranged between each pair ofsheets.

As a further modification the electrode group connections may bearranged, one group (either anode or cathode) in conductive radial lines81 and the other group (either cathode or anode) in concentric circularlines 82, as shown in Fig. 8. A single perforated insulating sheet issandwiched between the radial and circular electrodes 81 and 82. In thisembodiment the position of the illuminated spot (i. e., energized cell)will be dependent upon the radius (or range) and the bearing (or angle)circuits actuated, and may thus reflect range and hearing, or othersimilar data.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced other than as specifically described.

What is claimed is:

1. A display device comprising a gas-filled light-passing envelope, asandwich of alternately conducting and nonconducting layers, saidsandwich being mounted in said envelope and having one of its facespositioned in close proximity with said envelope, said layers having aplurality of holes formed therein and comprising a plurality of cellseach having a quantity of gas under pressure therein, each said cellhaving at least one conducting hole comprising a cathode therefor and atleast one conducting hole comprising an anode therefor, said conductinglayers being each electrically connected to selected ones of said holescorresponding to a coflguration resembling the predetermined indiciawhereby the cells individual thereto may be simultaneously fired, andmeans for connecting a source of power across selected pairs of saidconductors to fire the gas in the cells connected to the thus energizedconductors, said fired cells each being lighted by the luminous glowproduced adjacent its cathode and said glow being visible through saidenvelope.

2. A display device comprising a gas filled envelope, and a displayassembly mounted in said envelope, said assembly comprising a pluralityof perforated conducting laminations, selected perforations in saidlaminations having a non-conductive coating thereon, and an insulatinglayer between each of said conducting laminations, said perforationsbeing in alignment to form a plurality of discrete cells each having aquantity of gas under pressure therein, each said cell having at leastone conducting perforation comprising a cathode therefor and at leastone conducting perforation comprising an anode therefor, and means forconnecting a source of power across selected pairs of said conductinglaminations to fire the gas in the cells conductively connected to thethus energized laminations, said fired cells each being lighted by theluminous glow produced in the perforation of its cathode.

3. A gas-filled light-passing tube having a display assembly mountedtherein, said assembly comprising a plurality of glow cells each havinga quantity of gas under pressure therein, each cell having at leastthree electrodes connected thereto for control thereof, one of saidelectrodes comprising a cathode, a second an anode, and a third acontrol grid electrode positioned between said first and secondelectrodes, each said cell being lighted by the luminous glow producedadjacent its cathode upon application of ionization potential betweenits cathode and anode sufiicient to overcome bias potential applied toits grid.

4. A display device comprising a gas-filled light-passing envelope, adisplay assembly positioned within said envelope, said display assemblycomprising layers of alternately conducting and non-conducting members,said layers having a plurality of mutually cooperating groups of holestherein forming a plurality of cells, each of said conducting layershaving conducting members individual to preselected cells therein forsimultaneously firing one of said groups of cells, said cells containinga quantity of gas under pressure therein, predetermined members of saidconducting members being a cathode and an anode in said cells, each ofsaid cells being lighted by the luminous glow produced adjacent itscathode upon application of ionization potential between its cathode andanode.

5. A display device comprising a gas-filled light-passing envelope, adisplay assembly mounted in said envelope, said assembly comprising aplurality of conducting and non-conducting layers, a majority of saidindividual conducting layers having a configuration resemblingpredetermined indicia, said layers having a plurality of holes formedtherein and comprising a plurality of cells each having a quantity ofgas under pressure therein, each said cell having at least oneconducting hole comprising a cathode therefor and at least oneconducting hole comprising an anode therefor, said conducting layersbeing each connected to selected ones of said holes, and means forconnecting a source of power across selected pair of said conductors tofire the gas in the cells connected to the thus energized conductors,said fired cells each being lighted by the luminous glow producedadjacent its cathode and said glow being visible through said envelope.

6. A display device comprising a gas-filled light-passing envelope, adisplay assembly mounted in said envelope, said assembly comprising aplurality of conducting and non-conducting layers, said layers having aplurality of holes formed therein and comprising a plurality of cellseach having a quantity of gas under pressure therein, each said cellhaving at least one conducting hole comprising a cathode therefor and atleast one conducting hole comprising an anode therefor, each of saidconducting layers being each electrically connected to selected ones ofsaid conducting holes therein forming a configuration resemblingpredetermined indicia, and means for connecting a source of power acrossselected pairs of said conductors to fire the gas in the cells connectedto the thus energized conductors, said fired cells each being lighted bythe luminous glow produced adjacent its cathode and said glow beingvisible through said envelope.

References Cited in the file of this patent UNITED STATES PATENTS1,754,491 Wald Apr. 15, 1930 2,141,106 Boswau Ian. 3, 1939 2,595,617Toulon May 6, 1952

